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2025-08-29

Zenit-3M: M39x1/45.2 SLR

The Zenit-3M (Зенит-3М/Zenith-3M) is one of the M39x1/45.2 film SLR cameras.




The M39x1/45.2 is a lens mount that was developed in the USSR. However, it never gained popularity and was replaced by the more famous M42x1/45.5 mount.

One useful application of M39x1/45.2 cameras is their limited compatibility with Braun [Super] Paxette II M39x1/44 lenses. However, not all Paxette lenses can be mounted due to the presence of a mirror. Even if a lens can be mounted, the larger flange focal distance (45.2mm vs 44mm) prevents focusing on distant objects. Nevertheless, even these limited features can be useful in certain situations.

I prefer the back-door film loading of the Zenit-3M to the bottom-loading design of the Zenit, Zenit-S, and Zenit-3 cameras. Unlike the Zenit-E, the Zenit-3M doesn't have an instant return mirror. This design makes it safer to check the fitting of a Paxette lens. These are the reasons why I chose the Zenit-3M.

Posted by malykh в 10:42 0 comments

2025-08-27

Fish-eyes: Risespray 11/2.8 (FF) vs Pentax Q 03 3.2/5.6 (1/2.3")





And I compared the angle of view of these lenses. The Risespray (at f/2.8) was mounted on the Sony a7c (FF), the Pentax Q 03 (at f/5.6) was mounted on the Pentax Q (1/2.3").

1.
(Risespray)


(Pentax Q 03)

2.
(Risespray)

(Pentax Q 03)

3.
(Risespray)

(Pentax Q 03)

As expected, the angle of view of the Pentax Q 03 is not as wide as that of the Risespray 11/2.8. The vertical angle is smaller, too, despite the Pentax Q's 4:3 aspect ratio.
Posted by malykh в 18:46 0 comments

2025-08-25

NONS SL42 (II): NFE, Pentax K lenses

The NONS SL42 (II) camera is very demanding of a lens. Even with a large coverage, it is most likely not enough to take a picture without vignetting due to the shutter limitation. I demonstrated this with Pentacon Six lenses.

The NONS Format Extender (NFE) is included to solve this problem. It is a ~2x teleconverter (EF mount to EF mount) specially designed to work with the camera.

For example, the ISCO-Göttingen Iscovitar 50/2.8 (M42x1 lens). 

Without the NFE. ND4 filter, f/16, 1/250:




With the NFE. ND4 filter, f/8, 1/250:




My measurements show that the NFE provides a 1.89x magnification. The NFE decreases the intensity of the light (by about -2EV). Overall, the NFE degrades image quality. At least, I see higher chromatic aberrations. The NFE has only 3 optical elements.


Another question concerns using lenses with a Pentax K mount. Official information:

===
PK lens is only available for mounting on NONS format extender (lens + PK adapter + NFE + SL42). Since the aperture lever of PK lens will interfere with shutter module, it CANNOT mount on camera body (lens + PK adapter + SL42).
===

The second part of the statement is correct. The diaphragm actuator of a lens does not allow the lens to be mounted on the camera (with a Pentax K-Canon EF adapter).

However, the first part of the statement is incorrect. For the same reason, it is impossible to mount such a lens on the NFE. To solve this problem, I took apart the NFE and removed the front plate.




After modifying the NFE, it is possible to mount Pentax K lenses on it (with a Pentax K-Canon EF adapter). And putting the front plate back is much simpler than removing it.

Posted by malykh в 07:22 0 comments

2025-08-23

Ricoh GR IV announced

The Ricoh GR IV has been announced.






Overall, I like the Ricoh GR series. The GR IV is a nice evolution, and I don't mind the lack of a flash or viewfinder. However, dust on the sensor is an annoying issue. Unfortunately, there are no significant changes to address this problem (yes, I know about the different sensor coating and the thinner lens barrel).



See also related notes:
Image albums:
Posted by malykh в 08:30 0 comments

2025-08-21

Pentax Q 07 11.5/9 Mount Shield Lens

I found it.




The Pentax Q 07 Mount Shield Lens (11.5mm f/9) is the final lens in the so-called "Unique Lenses" series for Pentax Q cameras. I already have the Q 03 Fish-eye, the Q 04 Toy Lens Wide, the Q 05 Toy Lens Telephoto.




The Q 07 is an extremely small lens. It is smaller than its rear cap. Moreover, the lens can be used as a replacement of a body cap. That's why it is called the "Mount Shield Lens."




On the Pentax Q (1/2.3"), it is equivalent to a 64mm lens.

It is an electronic lens. It lacks a built-in leaf shutter and aperture control. Therefore, it behaves similarly to that of a manual focus lens with an adapter, with a few exceptions. First, a Pentax Q camera saves EXIF data with lens information (including the permanent f/9 aperture value). Second, a Pentax Q camera recognizes the focal length (11.5mm) for the sensor-shift image stabilization (SR). Third, since the lens lacks a focusing mechanism, it is neither an autofocus nor a manual focus.

The lens has 1 elements in 1 groups. Together with the focus-free design, it produces very specific images. In my opinion, the image quality is the worst in the "Unique Lenses" series. And at the same time, since you don't need to focus, the lens is the most fun to use (for me).

The Pentax Q 07, the Viltrox AF 28/4.5 FE (FF), the Samsung NX 30/2 (APS-C):



Posted by malykh в 07:51 0 comments

2025-08-19

Carl Zeiss Jena Triotar 80/4: Samples [1] - FF - f/4

Camera: Sony a7c (FF, 24MP)

The sharpness and contrast are better than expected for such an old uncoated triplet lens. Note that the triplet "soap bubbles" are almost absent.









Posted by malykh в 18:05 0 comments

2025-08-17

Pentax Q 04 6.3/7.1 Toy Lens Wide: Disassembled





It is made entirely of plastic. I had hoped to lubricate the focusing mechanism to improve its usability. However, that didn't help.



See also related notes:
Posted by malykh в 11:22 0 comments

2025-08-15

Certos rangefinder (A)

This is a Certos rangefinder ("Entfernungsmesser" by the German firm Certo).




The rangefinder is mounted on the Zarya camera.





The rangefinder is intended for Welta and Altissa cameras, so it is most likely the "Modell A".



How to use (in German):





Image albums:
Posted by malykh в 18:12 0 comments

2025-08-13

Mercedes-Benz G580 EQ rear axle

The Mercedes-Benz G580 is an electric vehicle. Each wheel has its own electric motor. Pairs of motors are combined for each axle and include a 2-speed gearbox (high and low ranges).

However, a unit is too heavy for the rear live solid axle. Instead, the G580 uses an uncommon De Dion suspension with Watt's linkage.

While this suspension is non-independent, but it is not a live axle. The half-shafts are positioned beside the axle rather than inside the axle tube.







Images from an electronic parts catalog:







Image albums:
Posted by malykh в 16:45 0 comments

2025-08-11

Mitakon Creator 85/2 II: Samples [2] - 135 film - f/2

Camera: Pentax Super A
Film: Ilford PanF Plus ISO 50 (135 B&W)

This is my favorite 135 film these days. The built-in TTL light meter of the Pentax Super A works correctly with the modified lens.








Posted by malykh в 14:27 0 comments

2025-08-09

Yuasa YBX3057 battery (B24R) for Suzuki Jimny

In 2013, I bought the GS Yuasa ECO.R LS ELS-B24R battery for my Suzuki Jimny. Recently, however, I accidentally deep discharged the battery. Now, the battery is unusable.

So, I bought a new battery to install in the Jimny: Yuasa YBX3057.




It is also a B24R battery. The "B24" indicates the dimensions. The "R" indicates the terminal placement.

Posted by malykh в 08:04 0 comments

2025-08-07

Carl Zeiss Jena Triotar 80/4 (M40x1): Long-focus uncoated (non-T) triplet lens

Another of my triplet lenses.




The Carl Zeiss Jena Triotar 1:4 f=8,5 cm (85mm, f/4).




This is the uncoated (non-T) version with an M40x1 mount. According to one source, this lens was manufactured in 1945.

The lens has 3 optical elements in 3 groups (yes, triplet). Though it is a long-focus lens, it is not a telephoto lens. That's why the body is so long for an 85mm lens, resembling earlier 135mm lenses.




It has 16 aperture blades. The aperture ring is clickless (f/4-f/32). 

The filter thread is 40.5mm.

The Triotar 85mm is surprisingly sharp for such an old triplet lens.

Posted by malykh в 08:36 0 comments
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